JPS5911013B2 - Earth retaining method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention is useful for excavating soft ground at the bottom of a river to increase the river area, for digging up soft ground for building underground structures, or for other purposes. This relates to the earth retaining method used when digging into the ground.

When carrying out excavation work in places where the soft ground continues deep underground, calculations are made to detect ground heaving (arc-shaped sliding) and the length of penetration of the earth retaining material is considered before construction. When the earth pressure is large and there are important structures nearby, the tips of earth retaining materials such as piles are penetrated deep into the ground into solid strata to stabilize the earth retaining structure.

However, in this method, the length of the earth retaining material is quite long, which requires a dog-shaped construction machine or construction device, and there are problems in that the construction site is restricted.

The object of the present invention is to provide an earth retaining method that advantageously solves the above-mentioned problems.

Next, the present invention will be explained in detail using illustrated examples.

1 to 4 show a first embodiment of the present invention. First, as shown in FIGS. 1 and 2, on the soft riverbed ground 3 of a river whose river area is to be increased, A large number of earth retaining walls 2 made of caissons with a rectangular cross section extending in the front-rear direction and support caissons 1 with a rectangular cross section extending in the left-right direction are installed between the front and rear earth retaining walls 2.
are arranged alternately so that the outer ends in the left and right direction are interposed,
and sinking the supporting caisson 1 and the earth retaining wall 2 by compression, internal excavation, or a combination of press-fit internal excavation,
The supporting caisson 1 is made to reach the hard ground 4 and is supported thereon, and the retaining wall 2 is relatively short within a range that can prevent heaving.

In this case, either the support cane 1 or the earth retaining wall 2 may be sunk first, or the support caisson 1 and the earth retaining wall that are lined up in series may be sunk from the rear to the front or from the front to the rear. They may be deposited sequentially.

Next, the supporting caisson 1 and the retaining wall 2, which are adjacent in the longitudinal direction, are connected by filling a bonding mortar between them or by other bonding means, and then Then, the river bed ground 3 between the left and right earth retaining walls 2 and the support caissons 1 is excavated to a level near the planned new riverbed level, and the outer walls 5 in the left and right direction of each support caisson 1 are left. The upper part of the wall was destroyed and removed to near the planned new river bed level, and the connecting concrete 6, which also served as the river bed, was poured between the upper parts of the left and right support caissons 1', and the upper parts of the support caissons 1' and the soil were Connecting concrete 7, which also serves as a riverbed side part, is cast across the inner surface of the retaining wall, and after filling the support caisson and retaining wall with filler earth and sand, bed concrete 8, which also serves as the riverbed, is cast.

5 and 6 show a second embodiment of the present invention, in which a large number of earth retaining walls 2 made of caissons with a rectangular cross section extending in the front and back direction are arranged in series along both left and right sides of the river bed ground. The left and right support caissons 1 are placed inside the row of earth retaining walls, and the outer ends of the support caisson 1 in the left and right direction extend over the ends of the earth retaining walls 2 adjacent in the front and back direction. placed so as to face each other,
Support caisson 1 has been sunk, and the entire upper circumferential wall of support caisson 1 has been destroyed and removed to near the planned new river bed level, but the other configurations and construction order are as follows:
This is the same as in the embodiment.

In the case of the second embodiment, the supporting caisson 1 and the retaining wall 2
When the earthen pipe retaining wall 2 is sunk, the support caisson 1 supports it against the back pressure. You don't have to leave it there.

Figures 7 and 8 show a third embodiment of the present invention, in which a support caisson 1 with a trapezoidal cross section and a short length that does not reach the hard ground 4 is sunk into soft ground. Then, the support pile 9 is inserted into the support caisson 1 and driven into the solid ground 4, and then the entire upper circumferential wall of the support caisson 1 is destroyed and removed to near the planned new riverbed level, The support pile 9 is cut at the upper part inside the support caisson,
In addition, a concrete floor 8 is cast in the upper part of the support caisson, and the support caisson 1 is supported by the support piles 9 via the concrete floor 8, but the other configuration and construction order are the same as in the first embodiment. Same as in case.

In the case of the third implementation row, short caissons can be used, which is economical, and the construction period can be further shortened.

9 and 10 show other examples of joints between supporting caissons and earth retaining walls. In the case of FIG. The protrusion 12 is formed by extending in the front-rear direction beyond the end plate 11, and the protrusion 12 is engaged with the outer side surface of the support caisson 1.

In the case of FIG. 10, the outer end of the support caisson 1 penetrates the inner wall plate 13 of the retaining wall 2 and projects into the interior of the retaining wall 2.

When carrying out this invention, a large number of steel sheet piles are interlocked with each other between support caissons 1 adjacent in the front and back direction and are driven into soft ground, and as the excavation of the planned area progresses, each steel sheet pile is The exposed portions may be connected by steel connecting beams to form the retaining wall, or any other type of retaining wall may be employed.

In the first embodiment, the thickness of the outer wall portion 5 of the support caisson 1 that is left as an earth retaining wall needs to be set to a thickness that can resist earth pressure.

Alternatively, the entire support caisson may be filled with earth and sand without placing concrete floor in the upper part of the support caisson.

According to this invention, a large number of support caissons 1 are sunk in the ground at a planned excavation position at intervals in the front-back direction, and earth retaining walls 2 are installed in the ground between the support caissons 10 lined up in the front-back direction. and then excavating the ground at the planned excavation position surrounded by the earth retaining wall and supporting caisson 1, etc.,
In addition, since the support caisson 1 and the earth retaining wall 2 are connected, even if a short earth retaining wall 2 that does not reach the hard ground is used, the support caisson 1, which is extremely stable against earth pressure, can be used to It is possible to support the earth retaining wall 2 in an extremely stable state, and also to prevent the earth retaining wall 2 from sinking due to its own weight. It is possible to build a safe earth retaining structure on soft ground, and there is no need to use long earth retaining materials, making it economical and easy to construct without the need for large construction machines or construction equipment. There are no restrictions on location, and the construction period can also be shortened.

[Brief explanation of the drawing]

1 to 4 show a first embodiment of the present invention, in which FIG. 1 is a plan view showing a support caisson and retaining wall installed on the river bed ground, and FIG. That A-
A sectional view taken along line A, FIG. 3 is a longitudinal sectional front view showing the completed earth retaining structure for increasing river area, and FIG. 4 is a plan view thereof. FIG. 5 is a longitudinal sectional front view showing an earth retaining structure for increasing river area constructed by the method of the second embodiment of the present invention, FIG. 6 is a plan view thereof, and FIG. 7 is a diagram of the third embodiment of the present invention. Vertical front view showing the earth retaining structure for increasing river area constructed by the method,
FIG. 9 is a plan view thereof, and FIGS. 9 and 10 are plan views showing other examples of the joint portion between the support caisson and the retaining wall. In the figure, 1 is a support caisson, 2 is an earth retaining wall, 3 is a river bed ground, 4 is a hard ground, 6 to 8 are concrete for binding that also serves as a river bed, and 9 is a support pile.

Claims (1)

[Claims] 1. A large number of support caissons 1 are sunk in the ground at the planned excavation position at intervals in the front-back direction, and earth retaining walls 2 are installed in the ground between the support caissons lined up in the front-back direction, and then the This earth retaining construction method is characterized by excavating the ground at a planned excavation position surrounded by an earth retaining wall 2, a supporting caisson 1, etc., and connecting the supporting caisson 1 and the earth retaining wall 2.